[1.20.4] Feat: Buffered flow timer

[emyfops]

This pull request implements a simple yet efficient timer using kotlin's flow
This is the code used for testing:

var time: Long
var time2: Long

timer(1000L) {
    time = System.currentTimeMillis()
    delay(1000L)
    info("Time1: ${System.currentTimeMillis() - time} milliseconds")
}

timer(1000L) {
    time2 = System.currentTimeMillis()
    delay(2000L)
    info("Timer2: ${System.currentTimeMillis() - time2} milliseconds")
}

There was an ever so slightly sleep deviation between 1 to 4 milliseconds, this was most likely caused by the System.currentTimeMillis(), shown as here